Electrical equipment today is presented on the market in a wide range. Among such products, the VVGng wire is especially popular.
For those who decided to carry out the wiring of low-voltage internal and external electrical networks, experienced craftsmen recommend using this particular conductive equipment. Information on the VVGng wire and its technical characteristics is presented in this article.
What is a product?
VVGNG wire is a type of VVG power cable, with the help of which power is supplied to indoor equipment, as well as to external cable structures and electrical appliances. Structurally, the VVG cable (GOST 16442-80) is represented by one or more conductive cores, each of which is equipped with its own insulation coating. In the power cable, the cores are twisted together and contain a common insulating sheath.
Abbreviation
The first letter in the electrical conductive system indicates the material of which the core is made. If it were aluminum, then the abbreviation on this wire would start with the letter “A”. Since it is absent in the VVG brands, it means that the conductors of all products are copper.
The letter "B" indicates the material of which the insulation coating is made: vinyl (polyvinyl chloride). Since “B” stands in the abbreviation twice, this means that the VVGng wire (GOST 53762-2010) is equipped with double vinyl insulation. Polyvinyl chloride is used for the manufacture of wire windings and the outer insulating layer.
The presence of the symbol "G" in the designation indicates that the cable does not contain armor. Due to this, the wire has sufficient flexibility, but at the same time is not protected from external mechanical influences.
What is the difference between VVGNG and VVG wire?
With a single laying of electrotechnical conductive products, they do not ignite. When jointly laying VVGng with other wires, in order to prevent burning of the cable, it is treated with a special anti-ignition solution. This is evidenced by the designation "NG". For the VVG base cable, the usual PVC insulation is provided, therefore, it does not have the presence of self-extinguishing and fire-retardant properties.
Types of wires
- VVG. Basic model with conventional polyvinyl chloride insulation. The wire may be ignited during joint installation.
- VVGng. The insulating layer is equipped with special halogen chemical elements that prevent cable ignition.
- VVGng Is. The wire is equipped with a halogen-free polyvinyl chloride insulating sheath. Using this type of VVG cable, electrical energy is distributed and transferred to equipment belonging to a similar voltage class. Due to its technical characteristics, the VVGng wire ls is primarily used in places with a particularly high probability of fire. The wire in the marking is still supplemented with the designation (Low Smoke).
- VVGng-frls. The insulating layer of this wire is also made of halogen-free materials. The cable has fire protection properties. When smoldering plastic insulation of this wire, a small amount of smoke is released.
Veins
This element is the basis of any conductive electrical product. VVGng wire may contain one or more copper conductors. Their number varies from 1 to 5. How much lived in the cable can be judged by its marking. Their number is indicated by the very first digit. For example, the VVGng 3x 2.5 wire is equipped with three copper conductors. Structurally, each of them can be a separate copper wire, or several twisted together.
You can also determine this by marking. The designation "M" is on those cables that contain multi-wire copper conductors. And vice versa, “0” is available on products with a single-wire core.
The form
Depending on how the wires are laid in the wire, VVGng products can be:
- Round. This form are cables that contain cores with small sections. Round-shaped wires are marked with the letter “K”.
- Segmental, or sectoral. Each of the veins is shaped into a certain part of the sector of the circle. Such wires are marked with the symbol "C".
- Flat. In such wires, the cores are laid along one plane. This form is typical for wires with a small cross section.
Section
In VVGng electrical products, this parameter varies from 1.5 mm square. up to 50 mm square The number of sections is indicated by the second digit. For example, in a VVGng 3 x2 5 wire, the wires have a cross section of 2.5 mm square. Nevertheless, there are also wires, the cross section of which can be 400 mm. sq. However, such cables are made to special order. If a parameter of 4 mm square is indicated, this does not mean that all five wires of the VVGng wire have such a section. 2.5 sq. mm is considered to be their optimal indicator, since the cross section of the neutral conductor and the ground conductor is usually smaller.
The best conductivity is for equipment that has a larger cross-sectional index. Conductivity is measured as the resistance of a conductor per thousand meters of length. For example, a cable whose cross section is 1.5 mm square. has a resistance of up to 12 ohms, and a product with a cross section of 50 mm square. - 0.39 ohms.
A wire can be operated if for a length of thousand meters its resistance will be in the range of 7-12 ohms. The resistance indicator is measured at a temperature not exceeding 20 degrees.
Insulation coating
The thickness of the insulation depends on such parameters of the wire as its nominal cross section and the voltage for which it is designed. With a cable cross section of 16 mm. sq. and a voltage of not more than 660V, the thickness of the insulation coating is 0.9 mm. If this wire will be operated at a voltage of 2.5 kV, then the insulation thickness should be 1 mm. For wire VVGng 3x2 5 mm square. at a voltage of 0.66 kV, it will not exceed 0.60 mm. For operation at 1 kV, the nominal insulation thickness is 0.70 mm.
Voltage
Before operation, the wire must pass electrical tests. The product, which is designed to operate at a voltage of 66 kV, is first tested for 10 minutes at a voltage of 3 kV. A wire rated for 1 kV must withstand 3.5 kV.
Bending ability
According to GOST, each wire, depending on the type, has certain mechanical characteristics. Those products that use stranded conductors can be bent to a radius of 7.5 cable diameters. Single-wire products easily bend to a radius of 10 diameters.
Temperature
The nominal temperature of the cable varies from -50 to +50 degrees. The optimum temperature regime for mounting the wire is: - 15 degrees. At lower temperatures, working with the cable is not recommended. Otherwise, according to electricians, the product will crumble and may even break.
Description of wire VVGng 3x2.5
The product consists of three conductive copper conductors. Polyvinyl chloride plastic (PVC) is used as an insulator. This material is also used as a winding. The wire in group laying is not flammable. No protective cover provided for the product.
Technical characteristics at a voltage of 0.66 kV
This conductive product at the specified voltage value differs in the following parameters:
- The nominal cross-section of the core is 2.5 mm square.
- A wire of one thousand meters weighs 135 kg.
- In cross section, the diameter is 9.3 cm.
- The core insulation has a thickness of 0.60 mm.
- A multiwire product has a minimum bend radius of 7 cm. If the core contains one wire, then the bend radius is 93 mm.
- The wire is rated for an allowable current load of 37 A (in the ground) and 28 A (in the air).
- In the event of a short circuit, 0.27 kA is considered acceptable for the wire.
- The electrical resistance of the insulating layer does not exceed 10 megohms.
Characteristics of the wire at a voltage of 1 kV
With the specified voltage value VVGng 3x2.5 has the following parameters:
- Cross section: 2.5 mm sq.
- A thousand meters long wire weighs 144 kg.
- A multi-wire product is characterized by a minimum bending radius of 0.73 cm, and a core with one wire is designed for bending with a radius of 0.97 cm.
- The thickness of the insulating layer is 0.70 mm.
- The electrical insulation resistance per 1 thousand meters is 10 megohms.
Wires are sold in twisted form, in drums. Their length varies from 500 to 7200 meters.
Application
A place for laying VVGNG wires can be:
- Dry and damp rooms: tunnels, canals, galleries, mines, collectors, industrial premises.
- Partially flooded structures in which weak, moderate or severe corrosive activity is noted.
- Special cable racks for blocks and bridges.
- Premises in residential and public buildings.
- Fire hazardous premises.
- Hazardous areas.
Conclusion
The warranty period for the wire is at least five years. According to consumers, it is possible to use VVGng much longer. The demand for this conductive product is explained by the ratio of its high technical characteristics and relatively low cost.